#include        <stdio.h>
#include 		<stdlib.h>
#include        <termios.h>

#define  oops(s,x) { perror(s); exit(x); }

int main(int argc, char *argv[])
{
        struct termios info;

        if ( argc == 1 ) 
		exit(0);

        if ( tcgetattr(0,&info) == -1 )          /* get attribs   */
			oops("tcgettattr", 1);

        if ( argv[1][0] == 'y' )
                info.c_lflag |= ECHO ;          /* turn on bit    */
        else
                info.c_lflag &= ~ECHO ;         /* turn off bit   */

        if ( tcsetattr(0,TCSANOW,&info) == -1 ) /* set attribs    */
               oops("tcsetattr",2);
	
		return 0;
}
